This invention relates to the field of coating substrates, such as discrete sheets or continuous ribbons of glass. More particularly, this invention relates to apparatus for dispensing glass coating compositions.
The prior art relating to apparatus for coating glass sheets, plates or like substrates includes U.S. Pat. No. 3,652,246 to Michelotti and Henery and U.S. Pat. No. 3,796,184 to Hawkins. Both of these patents deal with reciprocating spray coating devices for preferred use with a glass producing facility such as a float glass production unit, an annealing lehr or a facility including both. These patents illustrate coating composition dispensers mounted on a carriage which is operatively connected with a continuous traveling chain to reciprocate the carriage back and forth across a glass conveyer.
The prior art further includes British Pat. No. 1,116,460 which discloses a continuous traveling chain device having coating composition dispensers actually connected to the chain to travel about with it rather than merely reciprocating in response to its travel. This patent includes a description of an embodiment which provides dispensers for two coating compositions. However, the device shown in this British patent provides pairs of dispensers aimed parallel to the planes of travel of the chains on which they are mounted. As a result, the dispensers can only be facing a substrate to coat it during half their cycle of travel about the path of the chain.
The disclosure of this British patent also includes a description of one embodiment of a traveling chain device having coating composition dispensers mounted on the chain and oriented to direct coating composition normal to the plane of the traveling chain. Such a device is shown for either a single coating composition feed or individual dispenser tanks to batch feed each dispenser. This embodiment of a coating device does provide a capability to dispense coating composition toward a substrate during both halves of the cycle of travel along the traveling chain.
Nevertheless, the prior art does not provide any means for employing dispensers to continuously receive and dispense a plurality of coating compositions toward a substrate while providing for dispensing of coating composition from some dispensers traveling either half of a cycle along the path of a continuous traveling chain. Thus, the devices of the prior art are limited in capability to fully utilize the space taken by a traveling chain device. This is exemplified by the fact that if two coating compositions were to be applied to a substrate to make a two-film coating, it would be necessary to employ two complete traveling chain devices or to provide a device which failed to use both halves of its traveling cycle to apply coating composition to the substrate.
The present invention comprises an improvement to a device such as described in the British patent wherein dispensers are aimed normal to the plane of the traveling chains. The improvement provides a capability for independently employing plural coating compositions and for continuously delivering coating compositions to moving dispensers.